The present invention relates to a text mode color selection system for a monitor, and specifically relates to a text mode color selection system which can select the color tone of text mode voluntarily in accordance with the preference of a user.
A conventional text mode color selection system is, as shown in FIG. 3, constituted with a video memory 31 which can be caused to function in either a text mode or a general mode in accordance with the short or open of a text mode selection switch SW1, a buffer 32 which buffers and amplifies the output of the video memory 31, and a video output section 33 to which the output of the buffer 32 is input.
In accordance with the conventional system thus constituted, when a text mode selection switch SW1 is shorted in a state when video signals (R, r, G, g, B, b) are input, a low potential signal is applied to a text control terminal T of the video memory 31 and the video memory 31 assumes a text mode; thus, a video signal of one color such as green or amber is output from said video memory 31, and this one color video signal is applied to the video output section 33 through the buffer 32. Therefore only one color is displayed on a monitor in accordance with the text mode, by which is meant only one foreground color and only one background color, commonly referred to as monochrome.
On the other hand, when a text mode selection switch SW1 is opened, a high potential signal is applied to the text terminal T of the video memory 31 and the video memory 31 assumes a general mode; thus, a video signal of at least normally sixteen colors are output from the video memory 31 in accordance with the input of video signals (R, r, G, g, B, b), and these video signals are applied to the video output section 33 through the buffer 32. Therefore a color tone is displayed on a monitor.
However, in this conventional text mode color selection system, there have been the defects that it could not be conformed to a preference of a user because only one color may be selected in the case of text mode, and the color of the text mode could not be changed even if a user feels dissatisfied with the color of the text mode.